The Wireless Gigabit Alliance (WGA) Draft Specification 0.8 (WGA-D08), January 2010, herein incorporated by reference, defines modifications to both the 802.11 physical layers (PHY) and the 802.11 Medium Access Control Layer (MAC) to enable operation in the 60 GHz frequency bank (mmWave) for very high throughput wireless networks.
The personal basic service set (PBSS) is a self-contained network which includes one PBSS control point (PCP) and other stations (STAs). Wireless communication is possible to all member STAs of the PBSS. The infrastructure BSS is a network which includes one access point (AP) and set of stations (STAs) that have successfully synchronized with the AP using the JOIN service primitives and one STA that has used the START primitive. Membership in a BSS does not imply that wireless communication with all other members of the BSS is possible. An AP in BSS serves as gateway to access another network, e.g., the Internet.
Section 9.23 of WGA-D08 defines the mmWave channel access. Channel access by a mmWave station (mSTA) during the Beacon Intervals (BI) and is coordinated by a schedule. The schedule of the data transfer time (DTT) of a BI is communicated through the Extended Schedule element in the Announce frame or the mmWave Beacon frame. The Extended Schedule element contains the scheduling information of all allocations in the DTT.
FIG. 1 shows an example BI structure as defined in WGA-D08. In a BI, the DTT is an access period during which frame exchanges are performed between STAs. The DTT is comprised of the contention-based access periods (CBPs) and service periods (SPs). SPs are allocated to specific transmitting and receiving STAs, and CBPs are not specifically allocated to any STA.
Section 11.2 of WGA-D08 defines power management modes for a wireless device working under mmWave channels. Table 44 lists the various power states for PCP and non-PCP STAs during the various access periods of an Awake BI.
TABLE 44Power management states for an Awake BI (selected portions reproduced).PS non-PCP BI PortionPPS PCPSTACBP marked as PCP available AwakeAwakein the scheduleDozeCBP marked as PCP unavailable DozeAwakein the scheduleDozeSP with broadcast AID as Destination AIDAwakeAwakeNon-truncatable or non-extensible SP with AwakeAwakenon-PCP STA (excluding the PS STA) as DozeDozeSource AID and Destination AIDTruncatable SP or extensible SP with AwakeAwakenon-PCP STA (excluding the PS STA) as DozeSource AID and Destination AIDSPs allocated to itselfAwakeAwakeAll other SPsAwakeAwakeDozeDoze
However, the power management states are generically defined. There are many inefficiencies when working together with transmitting frames. Thus, there is a need for optimizing the switching of power management modes and transmitting frames.
Further, a mSTA may additionally work in an infrastructure BSS beyond the PBSS. An infrastructure BSS contains an AP providing access to another network, e.g., the Internet. All STAs within an infrastructure are required to be associated with the AP. WGA-D08 does not define a power saving mechanism for the infrastructure BSS; therefore, only 802.11 baseline power saving mechanism will be used in 60 GHz infrastructure BSS. Thus, there is a further need to implement a power saving mechanism for mSTAs that can work with both PBSS and 802.11 baseline power saving mechanisms.